Multi-line telephone system



Oct. 30, 1956 L w. DRol-:L

MULTI-LINE TELEPHONE SYSTEM 5 Sheets-Sheet 1 Filed March 2, 1954 INVENTOR.

Lou/s w. DRoEL ffm ATTORNEY Oct. 30, 1956 l.. w. DRoEL 2,769,035

MULTI-LINE TELEPHONE SYSTEM 3 Sheets-Sheet 2 Filed March 26, 1954 FIG. 4

Oct. 30, 1956 L. w. DRoEL 2,769,035

MULTI-LINE TELEPHONE SYSTEM Filed March 2e, 1954 S sheets-sheet 5 LI To I DISTANT CENTRAL A swITcHING POINT B P fr 4g 70w es2 @I To LINE To To LINE LINE United States Patent() MULTI-LINE TELEPHONE SYSTEM Louis W. Droel, Rochester, N. Y., assignor, by mesne assignments, to General Dynamics Corporation, a corporation of Delaware Application March 26, 1954, Serial No. 418,822 1c claims. (ci. 179-99) My invention relates to ltelephone systemsv in lwhich a f plurality of lines from a switching oiice terminate at a in the type of system contemplated in the above'para- Y graph have been provided with means to make it possible for the user to connect at will the telephone handset associated with a multi-line subset to any one of a number of lines terminating at the subset and further means independent of the connecting means forv placing a holding condition on a line so that the user could disconnect the telephone from the line by releasing the `first mentioned means without releasing the connection established to that line at the distant end. The mechanism provided in these subsets made it necessary for the user to observe the 'precaution of carrying out the prescribed holding and hangup operations in exact sequence in order to prevent the accidental release of or signalling to equipment at the dis- `tant ends ofthe lines terminated at the telephone subset.

Accordingly, it is an object of my invention to provide `a new and improved subset suitable for connecting to and placing a holding condition on any one of a number of lines terminating at the subset.

Another object' of my invention is to provide means in a subset for selectively connecting a telephone to any Yone of a number of lines terminating at the subset and means for automatically disconnecting the telephone from a selected line and establishing 'a holding conditionv on the selected line. v

Another object of my invention isto provide a subset v of the type described in the preceding object in whichv a f 1 previously established hold condition on a line is automatically removed upon connection of the. telephone to that particular line. i

Another object of my invention is to provide a subset of the type described in the preceding objects'whi'chzautomatically, upon the return of the telephone to its cradle, removes holding conditions from lines which have been placed in the holding condition. .t y: -1 i in a system of the type contemplated, -a pluralityf'of lines from a central switchingv point is extended lto a'plurality of subscriber subsets. Each of these subsets v,is

Y 2,769,035 Patented Oct. 30, 1956 ICC trolling means to remove the holding condition responsive to the operation of the connecting means to establish a connection between the telephone and the particular line.

Each subset is equipped with a manually operable hook= switch mechanism, operable to disconnect the associated telephone from a portion of the subset circuit. Other mechanical linkage between the hookswitch mechanism all of the holding means is provided in the subset and is effective to operate any holding means in the subset to remove the holding condition from the lines responsive to the hang up operation of -thel'hookswitch, thereby preventing the subscriber from accidentally leaving a holding condition on a line on hanging up his telephone.

The system contemplated also provides for an interconnecting line to which the telephone of each subset may be connected. Control of the establishment of such a connection is had by manually operable means at each subset, which with the previously mentioned connecting means, is effective to control the completion of such a connection. Means comprising a mechanical linkage between the interconnecting controlling means and line connecting controlling means is provided to transfer the telephone from any line terminating at the subset to the interconnecting line responsive to manual operation of the interconnecting means. The last-mentioned linkage is also operative to cause the interconnecting means tov open the connection between the telephone and the interconnecting lie responsive to the operation of the line connecting controlling means carried out to transfer the telephone from the interconnecting line to the line associated with any one line connecting means.

Further objects 4and advantages of my invention will become apparent as the following description proceeds and the features ,of novelty which characterize my invention will be pointed out with particularity in theV claims annexed to and forming a part of this speciiication. For a better understanding of my invention, reference may be had to the accompanying drawings,of which Fig. l shows a three-quarter view ofr assembled telephone subset embodying the principle ofmy invention;

Fig. 2 is a three-quarter view of the subset of Fig 1 with theshell and dial assemblies removed showingthe multi-position connecting switch and .theuholdingmeclranism in relation to the hookswitch control mechanism;

Fig. 3 is an exploded view'of a portion -of the subset shown in Fig. 2 showing details ofjthefhookswitch controlV mechanism and its relationship to theY cradle piece;

Fig. 4 is a View of ay portionv of -the subset shown lin Fig. 2 showing the details of the intercommuniating contact set control mechanism; c, I A A .Fig 5 is a single line'` schematic showing the arrangement of a plurality of anumberof subsets lin relation to i' ak plurality of lines terminating at thosesubsets; and

Fig. 6 is a schematic diagram of a typical subset suitable for use in the above-described system.

iReferring to the Ydrawings, each subset in the system f'consists cfa telephone 1 comprising transmitterA T and equipped with manually operablemeans 'forcontrolling j the establishment of connections betweenwthef associated vf 'telephone and all of the lines, one connection at ra time. Manually operable holding means in being possible. i i dividual Vto each line capable of controlling thei establishment of a holding condition'on -its associated lineare-also provided at each subset, theconnecting and holding means being mechanicallyinterlinked in. such away that oper?` ationot the holdingmeans associated with 'any oneQlineis eltective to controlthe connectingmeansfto. open a `connection between that line and the telephone infthe event that such a connection has been established. VThe same linkage is also effective, in the event that a holding condition has been imposed on a line, to cause the holding ,con-i receiver YRinto which the subscriber speaks and to which vhe listens respectively, and a base portion comprising subsetV basef and the equipment which it carries, all of the base' portion being coveredby shell assembly 2;

Referring tol-fig'. 6, means for controlling the. connection of -thev transmitter Tand receiverR ot telephone Y 1 to. the ,subset comprising'v hookswitch contacts I47 and .48 arerprovidedin the Vbase"portion. Contactsf47v and; v4S are arranged so that a connection between. transmitter to -it's own axis.

the subset on the plate portion 49 of hookswitch support 7 which is in turn carried by base portion 6. The component springs of stack S, all of which are xed at one end and free to move at the other, are held physically and electrically separated from each other and from the subset at their fixed ends by insulating -separator blocks. The assembled springs and separator blocks are compressed together and held against the plate portion 49 by means of clamping plate 62 which is urged toward the stack by means of screws 63. Clamping plate 62 overhangs the edges of stack S for reasons to be pointed out hereinafter.

Referring to the hookswitch springs as shown in Fig.

y3, dust cover assembly 64 comprising a substantially .between mounting plate 49 and the previously mentioned overhanging portion of clamping plate 62 and slotted portions 68 at the other end of assembly 64 which embrace the extended portion 69 of plate 49 are provided. The shell assembly 64 is retained in its position relative to the stack by means comprising top spring 66 which emerges from the opening 64a in the top of assembly 64 and bears against surface 67 thereby urging assembly 64 inwardly toward the iixed end of contact stack 8.

Means for controlling the movement of the springs comprising pusher 9 is carried by a part of the springs `at their free ends in stack 8. the latter .springs being movable under the control of pusher 9, preferably made of insulating material, to close and open contacts 47 and 48 as pusher 9 is raised and lowered, respectively.

Manually operable means comprising lever 12 for controlling movement of pusher 9 (and. conseouently. for controlling the hookswitch contacts 47 and 48) i-s pivotallv or rotatably attached to support 7 by means of pin Lever 12 in turn carries telephone receiving means comprising a pair of cradle pieces which are pivotally attached to lever 12 by means of pins 11, each pin passing through axially aligned bores in spaced-apart ears 12a and 12b normal to lever 12 and through opening 71 through each cradle piece 5, the latter being positioned between ears 12a and 12b. The axes of the bores in ears 12a and 12b are also parallel to the axis of rotation of lever 12 about pin 10.

In order to retain pin 11 in position, a spring 15 is fixed to lever 12, as by being passed through holes 14 in lever 12, for example7 and extends through slot 72 in engagement with annular groove 11a in pin 11, thereby preventing pin-11 from sliding along a line parallel The free end of spring 15 extends beyond cradle piece 5 and comprises means for manually depressing the spring to permit spring 15 to be moved out of engagement with pin 11 and thus permit efficient assembly and disassembly of the cradle piece 5 from hookswitch lever 12.

With shell 2 in its assembled position with respect to base 6, eachof cradle pieces 5 passes through one of the pairs of openings 36 and 36-1 in shell 2 and is guided by the walls of the openings as lever 12 is rotated about .pin 10.

A biasing spring 13 fixed at one end to clamping plate 62 and at the'other end' to leverv 12 urges lever 12 to rotate upwardly about its axis of rotationduring the time the telephone 1 is removed from cradlepieces 5.

Referring to Fig. y6, contacts 47 and `4S are arranged to be closed 4when telephone 1 is removed from the cradle pieces V5 and lever 12 is in its upper position so that the above described connection between the telephone and the subset portion is completed and opened when the 4 in the contemplated system may be connected to any one of a plurality of lines comprising lines L1 and L2 which extend to terminals in the base of the subset. Again referring to Fig. 6, means for connecting the sub set to lines L1 and L2 comprising contact sets 29 and? 29-1 are carried within the subset portion. These con tact sets each have normal and operated positions (conditions) and are wired in the well known series cut-off4 manner so that a connection from the subset conductors 37 and 38 is completed to conductors 42 and 43 by way of break portions of the contact sets when the latter are in their normal conditions, line L1 by way of the make portions of contact set 29 when the latter is in operated condition, and line L2 by way of the make portions of. contact set 291 and the break portions of contact set 29 when the former only is in operated condition. i

Mechanism for controlling the operation of contact sets 29 and 29-1 is provided in the subset portion at each subset in the system and is next described. Contact sets 29 and 29-1 are mounted on key plate 22 which is carried `by base 6. Means comprising multiposition lever 32 is pivotally attached to key assembly plate 22 by vertical pin 34 and is provided for moving each of thecontact sets 29 and 29-1, one at a time, between its normal and operated positions. Lever 32 is in normal position when it is at substantially right angles to the front edge 50 of base 6 and is movable in a horizontal plane to left and right of the normal position, the left and right positions constituting rst and second operated positions, respectively, which correspond to lines L1 and L2, respectively. Stop 51 comprising a projectionv on key plate 22 limits the travel of lever 32 as the latter is moved away from its normal position to determine these operated positions. Member 35 carried by the end of lever 32 which lies within the subset portioncooperates with the bottom spring of each of contact sets 29 and 29-1 when the lever is moved to the rst and second operated positions, respectively, to move the contact set associated with the line corresponding to the position to which lever 32 is moved from its normal to its operated position. The tension of the springs in any one contact set is operative to return each contact set to its normal position when lever 32 is moved to disengage member 35 from engagement with the bottom spring in that contact set. Member 35 is provided with la lateral portion 35a which cooperates with cam portions 35b of the bottom springs of contact sets 29 and 29-1 so that spring tension causes the lever to stay at -rest following its movement to either operated position and after the moving force is removed from it, this being a variation of the so-called locking type key assembly.

`line L2, are located in each subset of the system. Each such Vcontact set has 'a normal and an operated position and is arranged to open Eand to complete the shorting circuit of which it is la' part between the conductorsof the one terminating line with which it is associated when it is lin normal Vand operated positions, respectively.

Manually operable means comprising levers 24 land 24..-1 .are."y associated individually with and are individually operative for control-ling each of the holding Shaft '26 which is carried by journa'lled ears 40 of key. plate 22 is provided for pivotally carrying each of thehold levers so that cam members 30 and 30-1 carried by levers 24 and 24-1 respectively are brought into engagement with the springs of each of sets 28 and 28-1 to move the latter from their non-operated to operated positions'when the hold keys 25 or 25-1 attached Verate.

to the ends of levers 24 and 24-1 are moved Afrom their upper or norma-l to their .lower or operated positions. Tension of the springs in the sets is operativeto return the -contact sets to their normal positions when levers 424 and 24-1 are moved upwardly to their normal positions and members 30 and 30-1 are thereby disengaged from the springs `of the contact sets with which they coop- Members 30 and S0-1 lare so shapedthat levers 24 and 24-1 tend to stay at rest in both normal and operated positions following the removal of driving torce from the lever handle, -this being a varia-tion of the socalled locking type key.

First releasing means comprising cams such as 23 y.and 23-1 yare individually associated wit-h'each of the above'described holding means and holding controlling means as well as the one Ioperated position of lever 32 which corresponds to the line with which each controlling means vis associated. The purpose of each .cam is `to restore its -associated holding means from the latters operated to its normal position responsive to movement of lever 32 to the one operated position corresponding to the line with which the holding means is associated, thereby to remove automatically an existing holding condition trom the line at the .time that a connection is extended from the subset to the vline with which an operated holding `means and holding controlling means are associatedgconversely, each cam is also operative to restore lever 3'2 from one of its operated positions to its norm-al position responsive t-o the movement of `one of the holding levers to the latters operated position when the holding lever is associated with the line to which .the operated position of :lever 32 corresponds, thereby to disconnect automatically the subset from 4a line responsive to the establishment of a holding condition on the same line. To these ends, Vcams 23 and -23-1 are pivotally carried by pins 44 and l44-1, respectively. With one of the holding levers such as '24 in its operated position, operation of lever 32 to the left into its first operated position (corresponding to line L1) causes the left-hand edge of lever 32 `to engage surface `46 of cam 23 'and forces the cam to move in a clockwise direction about pin `44. Surface 45 of cam 23 .thereby is forced into engagement with the lower surface of hold lever 24 rand drives the latter from its lower (operated) ,position to its upper (normal) position tomove operating member 39 out of engagement with the outermost spring of contact set 28 so that the latter contact setis moved from its operated to its normal position to remove a holding coudition from line L1 Iat the same time t-hat lever 32 .causes spring lset 29 to be moved to yits operated position to extend a connection from the subset -to line L1. v'In the converse situation, i. e., when lever 32 is in one .of its operated positions such as the tirstlto cause the-extension of a connection from the subset to line L1, depressing hold lever 24 which is associated with line L1 lby operating key 2S to its operated position places a holding condition ron that line as previously explained, and, at the same time,

drives the lower surface of lever 24 into engagement with su-riiace 45 of cam 23, causing the cam to rotate vin `a Vcounterclockwise direction and forces cam surface ,46

Yassociated with line 'L1 it is pointed o ut -that the iirst releasing means .associated with line L2 functions in a similar manner. Y,

In order t-o provide for automatically rel-easing the holding condition from any yone vof the lines 'established at a subset in the contemplated system upon return of the telephone to itshookswitch, second releasing means compris- :ing mechanical link-age between hookswitch lever 1-2 and `the .holding controllingmeans comprisinglevers .24 and ltablished at the same subset von another line.

24-1 is provided. As previously described, return of the vtelephone 1 to hookswitch cradle 5 is operative to depress lever 12 and thereby 4openhookswitch contacts 48 to disconnect transmitter Tand receiver R from the subset and, consequently, from any line to which the subset has been connected. This linkage comprises first :and second linkage levers 17 Iand 18, respectively, and release bar 59. Depressing lever 12 to disconnect telephone 1 is effective to move the first linkage Ilever 17 about pivot pin 19 which is xed to hookswitch contact support 7; the movement of flared end S8 on lirst lever 17 engages and moves second lever 118 which is Vpivota-lly attached to the base 6 of the subset by means of pin 20. Ears 40 on plate 22 are provided with slots which slidably receive release 'bar 59 which `is moved to the right, as viewed in Fig. 2, responsive to the movement of levers 17 and 18 when the hookswitch lever l12. -is depressed. Slanting cam surfaces 60 of the hookswitch bar provided as part of suitable notches on release bar :59 `engage hold levers 24 and Z4-1 to move 4theflatter from their operated to their non-operated positions thereby restoring hold spring contact sets 2'8 and 28-1 to their normal positions. Restoration of contact sets 28 and 28-1 as described above removes hold conditions from lines L1 and L2 that existed prior to the above described hang 11p-operation carrie-d out by the subscriber.

On removal of vtelephone '1 from cradle pieces `5, lever l.12 is moved upwardly under the urging of spring 13 was previously vdescribed to allow first linkage lever 117 to be retracted from the position to which it was moved by depressing lever 1-2 Iand is kept in contact with lever 12 by the ur-gingtof helical fbias spring 16. This movement of ylever .1.7 also serves to disengage the dared portion 58 of lever 17 from linkage lever 18 and thereby make easier the movement of release bar l59 the left as viewed in Fig. 2 `responsive to the depression lof either -or both `of holding controlling levers 24 and 24-1 .to their operated positions when the latter'come into `engagement with slanting surf-ace 6@ of release bar 59.

In a system of the type contemplated, it is also de- :sira'ble to provide at each subset means for sending hashing supervision on the line to which` the subset is conlsystem using a subset Vhaving the above-described features, since operation of the hookswitch for ashing purposes is also operative to release a holding-condition es- Thus, it is necessary Vto provide suitable means for normally operating hookswitch contacts 47 and 48 which is independent of the hookswitch mechanism.

Such auxiliary hookswitch contact control means comprising topmost spring 6d of the spring stack 8 extending through the opening .64a .in dust cover assembly 64 and dlashing plunger "7GB, which is in turn carried by shell vthereby open the short comprising transmitter T between the conductors of the li-ne towhich the subset is con-- nected. l

To make possible to connect any one subset in the system to intercommunicating lineI, intercommunicating connecting means comprising contact set 52, incombination with previously described line connecting means@ -in the same subset, is provided tor controlling theV completion of a connection between the intercomrnuni'eating` line l and conductors 37 and 33 of the subset. Conltact set 4S2 and eachofthe line connecting means com-- prisiug .break portions of contact sets 29 and 29-.1 jointly 7 control the connection of conductors 37 and 38 to line I by way of conductors 42 and 43 within any one subset.

Means for controlling contact set 52 comprising lever 53 is pivotally carried on shaft 26. Operating member 54 carried on the end of level 53 is out of engagement With the innermost spring of contact set 52 and the latter is then in normal condition (contacts open) when member 53 is in the l-ower of its two positions as a result of lever 53 being in its normal position. When lever 53 is moved to its operated position responsive to manually depressing further controlling means comprising plunger 55, which is carried by the shell assembly 2, member 54 is raised to engage the innermost spring of contact set 52 to drive the contact set to its operated position and thereby close the contacts in that set. The operating member 54 and the innermost spring of set 52 with which member 54 cooperates are so shaped that the springs are held in either normal or operated position following the movement of lever 53 and after the moving force has been removed from lever 53, this being a variation o-f the so-called locking type key assembly.

Ears S6 carried by lever 53 are used as linkage between levers 32 and 53 to engage lower edges '57 of lever 53 as the latter is moved from its non-operated to its operated position to force lever 32 to be moved from either of its operated positions to its normal position, thereby restoring either operated line connecting means to normal position, to automatically transfer conductors 37 and 38 from their connection with either line L1 or L2 into connection with conductors 42 and 43 of the subset responsive to manual operation of lever 53 from its lnormal to its operated position. Conversely, ears 56 engage lower edges 57 of operated lever 53 as lever A32 is moved from its non-operated position to either of its operated positions to force lever 53 to move from its operated to non-operated position thereby causing contact set 52 to return to its normal position to open the connection between intercommunicating line I and the subset as represented by conductors 42 and 43 at the same time that conducors 37 and 38 are transferred from their connection to line I `to either li-ne L1 or L2, responsive to the operation of lever 32 as previously explained.

In the system contemplated which is schematically shown in Fig. 5, a number of lines having distant ends which terminate at a central switching point (not shown), extend to each of a plurality of subsets such as A, B, and P, which are identical to the subset described above. A subscriber at any one of the subsets connects his telephone to either of the lines L1 or L2 operating the manually controllable lever 32 as previously described. This same subscriber can, as he sees tit, place a hold condition on any or all lines terminating at his subset during the time that the telephone is lifted from the subsets cradle pieces and thereby automatically disconnect his telephone from the lines at the same time by placing the hold lever (24 or 24-1) associated with said any or all lines in its operated condition, as for example, by depressing one or both of levers 24 and 24-1.

When none or either of lines L1 or L2 has been placed in hold condition at his subset, the subscriber may connect his telephone to the other line by further operation of lever 32. Should the subscriber want to send flashing supervisoiy signals over the line to the central switching point, -he does so by operating flashing plunger 76 to open contacts 47 and 48 of the hookswitch contact assembly without causing the release of holding control levers 24 and 2li-i due to operation of the mechanical linkage which is controlled Iby and operative responsive to the operation of the hookswitch lever in the manner described above. Y

Signalling from the central switching point to the subsets in the present system is accomplished in any one of a number of ways which are not shown and because they are not a part of the present invention such as by the application of ringing voltage to the line at the distant 8 end to operate audible signals that may be attached to lines L1 and L2 at any or all of the subsets in the system, to indicate to the subscriber or subscribers when incoming calls are standing in the lines.

If the subscriber should desire to establish a connection to another one of the subsets in the system by way of intercommunicating line I `which is independent of lines L1 and L2, he does so by depressing the intercommunicating lplunger as previously described, thereby automatically transferring the telephone of the subset from the line L1 or L2 to which had been connected intercommunicating line I to which all subsets in the system have access. The subscriber signals the subset to which he Wishes to talk by means not shown, and which are not a part of the present invention.

When the subscriber hangs up his phone, the previously described linkage between the hookswitch .and the holding mechanism is rendered operative to remove holding conditions that have been placed on any lines at the particular subscribers subset, thereby freeing the line for further use.

While in the system contemplated only two lines are shown terminating at each subscribers subset, it is understood that my invention is equally effective when provision is made at each of the subsets in the system for terminating more than two lines. While increasing the number of terminating lines would necessitate the use of a somewhat different multi-position connecting mechanism, the principles involved in such a new machanism would be the same as the ones described above. v

The structural details of the cradle and hookswitch assembly are not part of the present invention, but are disclosed and claimed in the copending application of Louis W. Droel, Serial No. 283,942, tiled April 23, 1952, and assigned tothe same assignee as the present invent1on.

While I have shown and described my invention as applied to a specificA embodiment thereof, other modifications will readily occur to those skilled in the art. I do not, therefore, desire my invention to be limited to the specific arrangement shown and described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What is claimed is:

1. In telephone apparatus, a subset including a telephone, a plurality of lines terminating at said subset, connecting means in said subset individual to each of said lines for closing and opening a connection between each of said lines and said telephone, first controlling means in said subset for controlling said connecting means, holding means in said subset individual to each of said lines for establishing a holding condition on each of said lines, second controlling means individual to each of said holding means for causing said holding means to establish a holding condition on any one of said lines, and releasing means individual to and operable by said second controlling means for operating said first controlling means thereby eiecting the release of said lirst connecting means to disconnect said any one line from said telephone.

2. In telephone apparatus, a subset including a telephone, a plurality of lines terminating at said subset, connecting means in said subset individual to each of said lines for closing and opening a connection between each of said lines and said telephone, rst controlling means in said subset for controlling said connecting means, means in said subset for establishing and removing a holding condition on each of said lines, second controlling means individual to each of said holding means for causing said holding means to establish a holding condition on any one of said lines, and releasing means individual to said second controlling means and operable by said first controlling means for operating said second control means thereby effecting the release of said holding means to remove a holding 4condition -from said any one line.

3. .In `telephone apparatus, a subset including a telephone, a plurality of lines terminating at said subset, connecting means in said subset individual to each of saidlines for closing and opening a connection between each of said lines and said telephone, first controlling means in said subset for controlling said connecting means, means in said subset individual to each of said lines for controlling the establishment of a holding condition on each of said lines, second controlling means individual to each of said holding means for causing said holding means to establish a holding condition on any one of said lines, and releasing means individual to and operable Vby said second controlling means for operating said first controlling means thereby effecting the vrelease of said first connecting means to disconnect said vtelephone from said any one line and operable by said first controlling means for operating said second controlling means thereby efecting the release of said holding lmeans to remove a holding condition from said any one line.

4. The telephone apparatus of claim 3 wherein said subset includes hookswitch contacts for controlling the extension of a connection between said telephone and said subset, means for controlling said hookswitch contacts,.and other releasing means in said subset for moving said second controlling means operative responsive to operation of said hookswitch controlling means thereby effecting the operation of said holding means toremove holding conditions from alliof said lines.

5. In telephone apparatus, a plurality of subsets each including a telephone, a plurality of lines extending to each of said subsets, connecting means in each of .said subsets individual to each of said lines for opening and closing a connection between any one of said lines and said telephone of any one of said subsets, a single, first controlling means in each of said subsets movable to a plurality of positions each of which corresponds to one of said lines for causing said connecting means individual to said any-one line to close a connection to said telephone of said any one subset responsive to movement of said first controlling means of said any one subset to said position corresponding to said any one line, holding means in each of said subsets individual to each of said lines for establishing and removing a holding condition on said line to which it is individual, second controlling means individual to each of said holding means and each of said lines movable between first and Vsecond positions for causing said holding means individual to said any one line to remove a holding condition on said any one line responsive to movement of said second controlling means individual to said any one line from said second to said first position, releasing means individual to each of said second controlling means for restoring said second controlling means individual to said any one line in said any one subset from said second to said first position responsive to movement of said first controlling means in said any one subset to said position corresponding to said any one line, whereby a holding condition established at said any one subset on said any one line is removed responsive to movement of said rst controlling means to establish a connection between said telephone of said any one subset and said any one line.

6. In telephone apparatus, a plurality of subsets each including a telephone, a plurality of lines extending to each subset, connecting means in each subset individual to each of said lines for opening and closing a connection between any one of said lines and said telephone of any one of said subsets, a single, first controlling means in each of said subsets movable to a plurality of operated positions, each of which corresponds to one of said lines, and a normal position for causing said connecting means individual to said any one line to open a connection to Isaidftelephone of saidvany one subset-to said any oneline responsive to 'movement offsaid first controlling means fof rsaid any one subset from said position corresponding to said any one line to said normal position, holding means in each of said subsets individual to each ofsaid .lines for .establishing and removing a holding condition on said line to which itis individual, second controlling meansiindividual to each of said holding means and each 'of .said lines movable between first and second positions tion corresponding to said any one line to said normal position responsive to movement of said second controlling means individual to said any one line from said first-to said second position, whereby a connection between said telephone of said any one subset and said any one line is opened responsive to movementV of said second controlling means to establish a holding condition on said any one line.

7. In telephone apparatus, a plurality of subsets each including a telephone, a plurality of lines extending to each of ysaid subsets, connecting means in each of said subsets individualto each of said lines for opening and closing a connection between any one of said lines and said telephone of any oneof said subsets, a single, first Vcontrollingmeans in each of said subsets movable to a movement of said first controlling means of said-anyV one subset from and to, respectively, said position corresponding to said any one line, holding means in each of said subsets individually to each of said lines for establishing and removing a holding condition from said line to which it Vis individual, second controlling means individual to each of said holding means and each of said lines movable between first and second positions for causing said holdingmeans individual to said any one line to establish and Vremove a holding condition therefrom responsive to movement of said second controlling means individual to said any one line from said first to said second position and from said second to said first position, respectively, releasing means individual to each of said second controlling means for restoring said first controlling means in said any one subset from said position corresponding to said any one line to said normal position responsive to movement of said second controlling means individual to said any one line from said first to said second position, and for restoring said second controlling means in said any one subset and individual to said any one line from said second to said first position responsive to movement of said first controlling means in said anyone subset to said position corresponding to said any one line, whereby a connection between said telephone of said any one subset and said any one line is opened responsive to movement of said second controlling means to establish a holding condition on said any one line and a holding condition is removed from said any one line responsive to movement of said first controlling means to establish a connection between said telephone of said any one subset and said any one line.

means whereby said second controlling means are moved from said second to said iirst position when said hook- -switch contact controlling means is operated to disconnect said telephone of said any one subset from said any one line.

9. In telephone apparatus, a plurality` of 'subsets each including a telephone, a plurality of linesy extending to each of said subsets, connecting means in each of .said subsets individual to each of said linesfor opening and closing a connection between any one of said lines and said telephone of any one of, said subsets, a single, irst controlling means in each of said subsets movable to a plurality of operated positions, each of which corresponds to one of said lines, and a normal position for causing said connecting means individual to said any one line to close and'open-a connection-to said telephone of said any one subset' responsive to movement' of said first controllingmeans to and from,respectively, said operated position corresponding to saidany onel line, an intercommunicating line extending-to each of saidvsubsets, intercommunicatingconnecting-meansin each: of said subsets, said connecting'mean's and said interconnecting means jointly controlling the closing and opening of a connection between said intercommunicating line and said telephonevof said any one subset,*second-controlling,

means ineach of said subsets individual` to saidl'intercommunicating .connecting meansV movable between a nonoperated and anoperated position-folkcontrolling said intercommunicating connecting means andjfor moving said first controlling means from one ofsaid operated positions corersponding to 'said any one line tosaid' normal position responsive to vmovement of said second c ontrolling meansfjfrom said non-operated `to said operated position whereby the connection of said telephone of said any one subsetis transferred from said any one line to said intercommunicating line responsive tooperation of said second controlling means from said vnon-operated to said operatedpositi'on. l

10. In telephone appratuxa; subset-'including a tele-` phone, a plurality of' lines terminatingatv said subset, means comprising *rstspring set having normal and operated positions individual to" eachy of said lines for controlling the extension of a vconnection between theline to which said spring s etgisjindividual and `said telephone, means comprising a manually operable rst-lever-.injsaid subset having aV normal position and a plurality of operated positions, each of which corresponds to one of said lines and one of said rst spring sets, for moving said iirst spring set individual to any one of said lines to said operated position whereby a connection is completed between said telephone and said any one line responsive to movement of said rst lever to the one of said operated positions corresponding to said any one line, means comprising a second spring set having normal and operated positions individual to each of said lines and each of said vfirst spring sets for controlling the establishment of a holding condition on each of` said lines, means comprising a manually operable second lever having a normal and an operated position individual .to each of said second spring sets and the latters individual line for moving the individual said second springset between. said normal and said operated positions whereby a holding condition is placed on said any. onelineresponsive to movement of the one yof said secondlevers individual to said any one -line from said normal to said operated position, means comprising a third lever individual to each of said second levers for restoring its individual said second VAlever'from said operated to said normal position responsive to movement of. said iirst lever to the one or saidoperated positions corresponding to the line with which said second lever is individual and for restoring said iirstlever from the one .of said operated positions corresponding to said any one' line to said normal position responsive to the -operationof said second lever individual to said any one line from said normal to said operated position whereby -a hcldingcondition on any one of said lines is removed responsiveto the establishment of a connection between said telephone and said any one line and a connection between said Vtelephone and said any one line is opened :responsive to ythe establishment of a holding condition 0n said any oneline.

ReferencesCited in the le of this patent UNITED STATES PATENTS A OTHER REFERENCES v Automatic Electric Review, vol. 4, No. 1, March 1935, 

